3poundsonions (small, sweet variety such as Viidalia)
3tablespoonscoarse sea salt (use 2T if using fine tablesalt)See note
2scallions (and/or 2 ounces of garlic chives) - optional
2tablespoonssaeujeot (Korean salted and fermented shrimp)or 2T more fish sauce
1tablespoonsweet rice flour (chapssal garu, 찹쌀가루)or regular rice flour or all purpose flour
1tablespoonsugar - optional but use 1-2 T if not using sweet onions
To avoid tearing, put the onions in icy cold water for about 30 minutes before peeling. Cut onion in half from the tip to the bulb end, and remove the outer skin. Place the onion half, cut side down, on a cutting board, and cut it lengthwise at a slight angle into 2 or 3 even wedges.
Dissolve the salt in 2 cups of water and pour over the onions. Let sit for about an hour, flipping them over half way through.
Whisk together the glutinous powder and 1/2 cup of water. Simmer over low heat, stirring occasionally, until it thickens to a thin paste. Let it cool. Then, mix all the seasoning ingredients in a large bowl.
Drain the onions from salt water. Rinse the onion in fresh water once, and drain well.
Add the onions, and toss everything well until the onion slices are evenly coated with the seasonings.
Throw in the optional scallion and/or garlic chives. Store the kimchi in an airtight container. Keep it at room temperature for a day, and then refrigerate. Onion kimchi can be eaten right away, but the flavor develops as it ferments over a week or two in the fridge.
A couple of tablespoons of vinegar in salt water can help remove the spicy bite of the onions. I don't find it necessary with Vidalia onions, but it will be helpful with more spicy onions.